How to Make Plastic Out of Milk

As the daughter of a (former) dairy farmer, I love milk and all its derived dairy products (e.g., cheese and butter). However, it wasn’t until my colleague Michele highlighted a kid science app that I realized milk is a great science medium as well. In fact, I recently discovered mixing vinegar with milk will create moldable plastic. Not only is this milk-derived product fun for kids and adults, but it also offers a history lesson: the resulting substance was used before petroleum-based plastic was available. Watch the video to learn about a fun kitchen experiment and potential handmade gift opportunity all in one package.


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Sara Klink

Technical Writer at Promega Corporation
Sara is a native Wisconsinite who grew up on a fifth-generation dairy farm and decided she wanted to be a scientist at age 12. She was educated at the University of Wisconsin—Parkside, where she earned a B.S. in Biology and a Master’s degree in Molecular Biology before earning her second Master’s degree in Oncology at the University of Wisconsin—Madison. She has worked for Promega Corporation for more than 15 years, first as a Technical Services Scientist, currently as a Technical Writer. Sara enjoys talking about her flock of entertaining chickens and tries not to be too ambitious when planning her spring garden.


  1. Nice, Sara…plastic from milk casein. But i was worried for a minute there. Many of my favorite recipes for baked goods use buttermilk but I rarely have that on hand. So to make a buttermilk-like substance, I add vinegar (or lemon juice) to milk…something like 1 teaspoon of vinegar to 1 cup of milk. Good news is that i don’t separate out the casein…or wait 48 hours. And the baked results are usually edible…

  2. Hi Kari,

    I was thinking about the buttermilk substitute as well when watching the video but the milk is not usually heated nor stirred so long so I figured I was safe.

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